1. Field of the Invention
The present invention relates generally to marking for identification purposes. More particularly, the present invention relates to systems and methods for the tagging of articles with tags in predetermined locations.
2. Description of the Related Art
The tagging of plastic articles is very desirable for a variety of applications, including piracy protection of optical storage media. Optical storage media are in widespread use today. Optical storage media may be used to hold music, data and software, and have become the standard medium for distributing large quantities of information in a reliable package. The number of illegal CD and DVD copies throughout the world has increased as a result of the computer age. One reason for this trend is that home PCs, blank CD-Rs, blank DVD-Rs, and fast CD and DVD burners have become cheaper and more widely available, so virtually anyone can setup a small disk manufacturing plant. Music and software piracy problems affect every sector of their industries. Retailers, distributors, artists, composers, publishers, and record companies are all affected when customers are sold a pirated copy rather than a legitimate recording. Hundreds of millions of counterfeit CDs and DVDs are thought to be created each year, and hundreds of millions of CD-Rs and DVD-Rs are sold every year.
The use of tags for identification in plastic materials is known in the art. UV and near-IR fluorescent dyes have been added to polymers for identification purposes. In one conventional approach, a near infrared fluorophore is incorporated into a polycarbonate substrate. One disadvantage of these conventional methods is that incorrect signals may be produced if any of the dyes age or leach under normal use conditions, which may include exposure to UV light, high ambient temperatures, etc. In addition, additives in polymers may alter the ratio of fluorescence intensities.
For the tagging of optical media, it would be advantageous to apply a tag onto a well-defined location, or locations, on an article rather than on a whole surface. In addition, it would be advantageous to apply such a tag onto an article while it is undergoing a spin-coating process, which is the commonly-used method for applying coatings to optical media due to the quality of the resulting coating, high speed and low manufacturing cost of the process.